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What do I need to look out for when working with hazardous gasses?

Gasses must be handled with care. Special rules apply to toxic and flammable gasses. Mixing requires permission.

  • For the ordering, storage and working with toxic and/or flammable gasses follow the locally applicable procedures. 
  • Leave the connection and disconnection of gas cylinders to qualified persons.
  • Before using a gas read its safety information sheet (MSDS). 
  • Be certain about the content of a gas cylinder. Only the embossed detail in the head of the cylinder provides absolute certainty about the contents. Therefore do not depend on the colour of the cylinder and the thread of the valve. 
  • Never allow the gas cylinders to heat up. The maximum safe cylinder temperature is 50ºC. 
  • Keep a safe distance from the dial of the manometers. In the case of a leaking Bourdon tube the dial and glass of the manometer can fly off.
  • Prevent internal contamination of the cylinders by:
    - using non-return valves if necessary;
    - always leaving a small residual pressure in the cylinder;
    - Closing the valve after use. Follow the guideline (see the frame on this page) for the opening and closing of gas cylinders.
  • If you suspect that the cylinder is contaminated warn the person responsible for gasses or the supplier. 
  • Immediately transport empty cylinders to the gas cylinder storage facility and affix a sign with the word 'empty' to the cylinder.
  • You may not fill gas cylinders yourself.

Toxic and/or flammable gasses

  • Consider the installation of a gas leakage detection system in the working space/ and or storage space. This is required if the threshold limit value (TLV) can be exceeded. Ask your health & safety coordinator about this.
  • Draw up a plan in advance for the safe use of the gas together with the person in charge or your health & safety coordinator. The gas may never flow freely into the room.
  • Assume the most dangerous situation when drawing up safety measures, for example, a serious leakage occurs (torn main pipe) and the main valve can no longer be closed. 
  • Position the detectors low in the room for heavy gasses and high for light gasses.
  • Some gasses are hardly toxic but can yield extremely poisonous products in the event of a fire, naked flame or (over)heating. Examples: the isolation gas SF6 and the cooling agent freon. Bear this in mind.
  • For hazardous gasses draw up an emergency plan together with the safety officer or the health & safety coordinator. The measures should be known to colleagues in the vicinity. 

Self-composed mixed gasses

  • In exceptional cases you may compose your own mixed gasses. You must first of all gain permission from the responsible safety officer. 
  • Keep the gas pressure in the cylinder as low as possible.
  • Never use a randomly chosen (used) gas cylinder but always a new one.
  • Label the cylinder, even if it is only to be used briefly. Never change anything to the embossed data of the cylinder. Ask the responsible person how to deal with such information.

Lecture bottles

  • The general rules for gas cylinders also apply here. However, these cylinders may be used outside of a gas cylinder storage facility. See also 'toxic and/or flammable gasses'. 
  • Lecture bottles not in use should always be kept in a gas cylinder storage facility. 


  • Gas cylinders must be inspected on a regular basis. See the leaflet (in Dutch only) re-inspection periods per type of gas.
  • All appendages (regulators, valves, pipes) must be inspected regularly (preferably annually).


The Environmental Management Act prohibits the storage and use of gas cylinders for which the inspection period has lapsed. When ordering gas cylinders (so lecture bottles as well) please bear in mind that the content must be used and disposed off within the re-inspection period.

Confidental Infomation